The city of of Parma and its surrounding area were during the
early middle age ruled by bishops but became a self-governing commune 1115.
Like many other Italian communes came to power in Parma eventually in the hands
of one man, a so called signore. In 1346 took Milan over the control over Parma
and it became a part of Papal States 1512. Pope Paul III enfiefed Parma and
Piacenz to his illegitimate son Piero Lodovico as duchies 1545. As a result of
the War of the Austrian Succession was the duchy Guastalla added to Parma 1748.
After a brief period as a part of France was Parma given to Napoleon's wife Marie
Louise of Habsburg by the Congress at Vienna. The collateral branch of the house
of Bourbon that had previously ruled Parma became instead dukes of Lucca. When
Marie Louise died 1847 was the house of Bourbon temporarily restored but they
were deposed again during the unification of Italy 1859-1861.

Parma unites with Sardinia 1860, which is transformed into
the kingdom of Italy
1861

* = Parma was 1808-1814 a French departement called Taro. The titles
"duke of Parma" and "duke of Piacenza" was then used by
the French officials Jean-Jacques Régis de Cambacérès and Charles François Lebrun.
Napoleon's sister Pauline became already in 1806 duchess of Guastalla.